Secure Over-The-Air Firmware Upgrade

2. The system of claim 1, wherein the delivery mode is an indirect offline delivery mode that enables the server to transmit, to the controller, the encrypted firmware upgrade (i) to be stored on the controller at a first time when the embedded device is not available to receive the encrypted firmware upgrade and (ii) to subsequently be delivered to the embedded device at a second time later than the first time when the embedded device becomes available to receive the encrypted firmware upgrade.

3. The system of claim 1, wherein the key encryption key is a general embedded device key that is obfuscated within a previous version of firmware related to the firmware upgrade.

4. The system of claim 1, wherein the firmware upgrade includes a general embedded device key to be utilized for a subsequent firmware upgrade.

5. The system of claim 1, wherein the firmware upgrade is programmed to be stored on the controller until the embedded device requests for the firmware upgrade.

7. The system of claim 1, wherein the key encryption key is a session key between the server and the controller.

9. The system of claim 8, wherein the key encryption key is a second session key between the server and the embedded device.

10. The system of claim 9, wherein the second session key is a unique key specific to the embedded device or a device type associated with the embedded device.

11. The system of claim 8, wherein the processor is further programmed to verify one or more immutable identifiers associated with the embedded device and digitally sign, prior to the transmission and based on a digital certificate related to the one or more immutable identifiers, at least one of the encrypted firmware upgrade or the encrypted firmware key.

12. The system of claim 8, wherein the processor is further programmed to transmit, to the embedded device, a list of firmware version numbers and associated expiration dates to enable the embedded device to determine whether to request for the firmware upgrade.